WASHINGTON — Alabama Sen. Jeff Sessions fervently rejected "damnably false" accusations of past racist comments Tuesday as he challenged Democratic concerns about the civil rights commitment he would bring as Donald Trump's attorney general. He vowed at his confirmation hearing to stay independent from the White House and stand up to Trump when necessary.

Sessions laid out a sharply conservative vision for the Justice Department he would oversee, pledging to crack down on illegal immigration, gun violence and the "scourge of radical Islamic terrorism" and to keep open the Guantanamo Bay prison in Cuba.

But he also distanced himself from some of Trump's public pronouncements.

He said waterboarding, a now-banned harsh interrogation technique that Trump has at times expressed support for, was "absolutely improper and illegal."

Though he said he would prosecute immigrants who repeatedly enter the country illegally and criticized as constitutionally "questionable" an executive action by President Barack Obama that shielded certain immigrants from deportation, he said he did "not support the idea that Muslims, as a religious group, should be denied admission to the United States."

Trump earlier in his campaign called for a temporary total ban on Muslims entering his country but has more recently proposed "extreme vetting."

Sessions asserted that he could confront Trump if needed, saying an attorney general must be prepared to resign if asked to do something "unlawful or unconstitutional."

Nothing new came out of the hearing that seemed likely to threaten Sessions' confirmation by the Republican Senate.

Yet as he outlined his priorities, his past — including a 1986 judicial nomination that failed amid allegations that he'd made racially charged comments — hovered over the proceedings. Protesters calling Sessions a racist repeatedly interrupted and were hustled out by Capitol police.

Sessions vigorously denied that he had ever called the NAACP "un-American." He said he had never harbored racial animus, calling the allegations — which included that he had referred to a black attorney in his office as "boy" — part of a false caricature.

"It wasn't accurate then," Sessions said. "It isn't accurate now."

He said he "understands the history of civil rights and the horrendous impact that relentless and systemic discrimination and the denial of voting rights has had on our African-American brothers and sisters. I have witnessed it."

"I know we need to do better. We can never go back," Sessions said. "I am totally committed to maintaining the freedom and equality that this country has to provide to every citizen."

Politics got its share of attention, too, with Sessions promising to recuse himself from any investigation there might be into Democrat Hillary Clinton, whom he had criticized during the presidential campaign.

Trump said during the campaign he would name a special prosecutor to look into Clinton's use of a private email server, but he has since backed away. The FBI and Justice Department declined to bring charges last year.

Sessions, known as one of the most staunchly conservative members of the Senate, smiled amiably as he began his presentation, taking time to introduce his grandchildren, joking about Alabama football and making self-deprecating remarks about his strong Southern accent.

He has solid support from the Senate's Republican majority and from some Democrats in conservative-leaning states.

But he faces a challenge persuading skeptical Democrats that he'll be fair and committed to civil rights, a chief priority of the Justice Department during the Obama administration, as the country's top law enforcement official.

Sen. Dianne Feinstein, D-Calif., asked whether he could be trusted to enforce the laws he has voted against, including expanded hate crime protections. He said he could, noting that he accepted the Roe v. Wade opinion on abortion as the law of the land even though he personally opposed it.

Feinstein said, "There is so much fear in this country. I see it, I hear it — particularly in the African-American community, from preachers, from politicians, from everyday Americans."

If confirmed, Sessions would succeed Attorney General Loretta Lynch and would be in a position to reshape Justice Department priorities not only in civil rights but also environmental enforcement, criminal justice and national security.

He said he supported continued use of the Guantanamo Bay detention facility for terror suspects, a sharp departure from an Obama administration that has supported prosecuting militants in American courts.

And he hinted he'd be less eager than Obama's Justice Department to prod city police departments into court-enforceable improvement plans, known as consent decrees, to resolve allegations of pervasive civil rights violations. He said he did not consider it fair to criticize an entire department for what might be the actions of just a few.

"We need to be sure that when we criticize law officers, it is narrowly focused on the right basis for criticism," he said, adding that "to smear whole departments places those officers at greater risk."

Sessions was first elected to the Senate in 1996 and before that served as Alabama attorney general and a U.S. attorney.

He's been a reliably conservative voice in Congress, supporting government surveillance programs and opposing a 2013 bipartisan immigration bill that included a pathway to citizenship for the estimated 11 million immigrants living in the U.S. illegally.

In a dramatic turn, Senate colleague Cory Booker of New Jersey — one of three black senators — is to testify against Sessions on Wednesday. Booker's office says that will be an unprecedented instance of a senator testifying against a colleague seeking a Cabinet post.

In a statement, Booker accused Sessions of having a "concerning" record on civil rights and criminal justice reform.